Generally, a technology that detects an obstacle of a vehicle uses an ultrasonic sensor disposed within the vehicle. However, the ultrasonic sensor may not detect the obstacle accurately based on the positioning of the sensor within the vehicle and surrounding environment. In addition, when detecting the obstacle, the ultrasonic sensor may incorrectly detect the obstacle where there no obstacle is present due to an unevenness of the ground or sound source disturbance to generate a false alarm. Hence, reliability related to the obstacle detection may be degraded.
Further, when detecting the obstacle using the ultrasonic sensor, the obstacle may be detected only in a direction in which the ultrasonic sensor is mounted. To detect the obstacle in all directions of the vehicle, the ultrasonic sensor should be mounted in all directions of the vehicle.